1. Field of the Invention
The present invention relates generally to the application of resistive materials to substrates, and more particularly to a method for forming resistive gradients, patterns, and uniform coatings on substrates, as well as for incorporating such coating materials into structural laminates for radar cross section (RCS) reduction, field shaping, antennae, current control and shaping, field current and power absorption, and EMI suppression.
2. Description of the Related Art
The use of electric fields to create patterns of regularity or irregularity using various types of wet or dry media has been known for a long time.
U.S. Pat. No. 2,097,233 to Meston discloses an apparatus employing electrical deposition for coating or decorating a surface with a material which is conveyed to the vicinity of the surface as a finely divided suspension and then directly deposited on the surface in a pattern.
U.S. Pat. No. 4,545,536 to Avidon and U.S. Pat. No. 4,748,043 to Seaver et al. disclose electrostatic coating systems for applying very thin coatings of wet or dry materials on substrates.
It is also known from U.S. Pat. No. 3,992,212 to Youtsey et al. and U.S. Pat. No. 4,452,844 to Prabhu et al. to provide electrical resistor inks for use in the formation of resistors in electrical circuits in such applications as printed circuit boards and ceramic substrates bearing thick film circuits.
Against this background of known prior art, applicant has developed a new, more efficient, cost-effective process for forming resistive gradients, patterns, and uniform coatings on woven or porous substrates using an inkjet application apparatus and an inorganic conducting polymer (ICP) developed by the assignee of the present invention, and described in greater detail below.